Every system your system will ever communicate with has individual fields like that. It's much easier to concatenate an address or name together from separate fields than to split them apart after the fact.
I was referring just to the street address part, though, which is almost always entirely freeform, or at least is up to complex and opaque rules that vary by city. This is what textareas are for: unstructured input of a string (not prose writing, but simply a string) that may require newlines in it.
Coming right after the street address field would, of course, be separate single-line input fields for the city, country, etc... but the street address itself should allow as many lines as you need.
So was I. Every system my software communicates with has an "Address1" and "Address2" field. Ok, some only have an "Address" field. They don't except newlines and most of the time those fields are limited to 50, 100, or 256 characters.
House Name,
Road,
Village,
Town,
County,
Country (if applicable)
Post Code.
My address structure is:
Flat Number - Building,
Road,
City,
Country,
Post Code
Some multi-input address forms require that I enter both a city and a county, which in the case of Londoners means you end up putting London twice. The only important parts of the address (for most uses, including credit card processing) are recipient name, house/flat name/number (actually, not sure about this - it might not be necessary) and Post Code.
So why not just have explicit inputs for those fields which are always required, and allow a more fuzzy input for everything else in the form of a textarea? It also means you're more likely to be able to deal with addresses in countries that use slightly different systems.
From a credit card perspective, actually, you don't even need the house/flat name/number. As you can see easily on the basecamp paid signup page, all you need is:
First/Last name
Card number
Expiry Date
Billing Zip
Worth noting that those extra billing fields like address and all that help cut down fraud (as well as signups...) so if your business is not b2b and relatively fraud-free, you probably should keep the extra fields for anti-fraud checks.
Not to mention, if you have those fields you'll pay less for the credit card transactions. I just recently added a bunch more address fields to a CC form to reduce the fees on transactions.
